1. Field of the Invention
The embodiments discussed herein are related to a laser source having a laser device and an optical waveguide.
2. Description of the Related Art
A structure for reducing the reflection of light emitted from a laser diode (LD) at the laser diode and air interface is disclosed in Patent Document 1 (Japanese Laid-Open Patent Application Publication No. H2-146778). Patent Document 1 discloses a laser device in which a waveguide in a non-excitation region, outside an excitation region, is curved.
Optical devices that are coupled to the laser device for receiving laser light are, for example, an optical fiber and an optical waveguide. One example is a second harmonic generation (SHG) laser device that is a combination of a laser device and an SHG device. An example of a structure for coupling a laser device with an optical waveguide is disclosed in Patent Document 2 (Japanese Laid-Open Patent Application Publication No. H7-209560).
However, the direct coupling of the conventional laser device with an optical device has problems of large coupling loss or troublesome alignment of optical axes. Generally, a lens is inserted between the laser device and the optical waveguide. However, in this configuration, loss can be caused by the lens and the number of components increases because of the lens, driving up costs. Further, alignment of optical axes between the three parts including the lens is required and the size of the entire device becomes larger.
Although the structure disclosed in Patent Document 2 does not require a lens, end faces of the laser device and optical waveguide to be in contact with each other cannot be installed to be parallel, making the alignment of optical axes difficult. For the alignment of optical axes, it is preferable that the positioning of adjacent devices be determined along a z-axis, the optical axis, and with respect to x- and y-axes which are perpendicular to the z-axis.
However, according to Patent Document 2, positioning of optical devices along one axis cannot be determined independently: while one axis (for example, the z-axis) is adjusted, positions along the other axes (x and y axes) move. As a result, positions along multiple axes must be adjusted simultaneously and thus, the position adjustment of the devices becomes difficult.
In order to directly couple optical devices, the optical devices need to be placed in a close range. When the optical devices are coupled in an inclined state, end faces of the optical devices may contact each other, making adjustments to the alignment of optical axes impossible or on the contrary, the end faces of the optical devices may be spaced apart from each other, making direct coupling impossible.